James Murdoch at the Commons culture committee earlier this week. Photograph: Reuters

8.46am: Peter Walker writes: Welcome to live updates on the phone hacking story, which thus far today appears to be dominated by two main strands:

• Questions over James Murdoch's insistence to the culture select committee on Tuesday that when he approved a big payout to Gordon Taylor, chief executive of the Professional Footballers' Association, he did not know phone hacking at the News of the World went beyond one "rogue" reporter. Not so, according to Colin Myler, last editor of the now closed paper and Tom Crone, News International's former legal manager – they have released a statement saying they did inform Murdoch of an email suggesting the practice went further. It's a potentially very big moment: two figures near the heart of the affair accusing their former boss of misleading parliament.

• Further bafflement over Andy Coulson's relatively low security clearance when he was Downing Street communications chief. Former occupants of the same role have lined up to question how he carried out such a sensitive, generalist task without access to the most secret information. The Guardian has confirmed that Coulson's immediate predecessors were all checked to "developed vetting" level – and his successor Craig Oliver and former deputy Gaby Bertin are being checked to that level now. But Coulson was only checked to the level below: "security check".

There will, of course, be plenty more.

8.53am: Peter Walker writes: In a slight break from tradition I'll round up a few of the more interesting stories elsewhere before pointing you towards other aspects of our coverage.

• Tom Watson, the Labour MP who's very much helped lead the way over the story, believes the scandal is likely to spread to allegations of email interception and similar computer-based hacking. He tells the Daily Telegraph that as well as the likes of Glenn Mulcaire it's likely there were "other private investigators who have different skills", for example planting Trojan files onto hard drives. Gordon Brown made similar allegations in parliament last week.

• According to the BBC, the FBI is to contact Jude Law over claims the actor's mobile phone was hacked during a US visit, potentially leaving News International open to prosecution in America.

• Various papers, among them the Mail, report that Neil Wallis, the NoW deputy editor-turned freelance PR adviser for Scotland Yard, went to Downing Street to see Andy Coulson following David Cameron's election.

9.10am:Peter Walker writes: And finally... a few items from the Guardian:

Raynsford told the Commons on Tuesday that the official had endured "disgraceful and illegal" hacking, as well as media harassment.

But O'Donnell said today that after the civil servant, from the education department, raised concerns about being followed by journalists and mysterious calls during the night, the matter was "thoroughly investigated" and no evidence of wrongdoing was found. He quoted a letter from Sir David Bell, the most senior civil servant at the department, who said the official later confirmed that neither the police or his mobile phone company could find anything wrong.

O'Donnell said to Raynsford:

I completely understand why you raised this issue in the house and accept that it was in good faith and the result of a genuine misunderstanding.

Like Margaret Thatcher with her famous use of the dialect word "frit", Cameron likes to do the common man bit. His favourite resource is the mass media as with the Michael Winner "calm down" quote. In this debate it was the use of the Sun's offensive headline "Gotcha", though in this context, you might have expected him to have avoided anything that might imply an overly familiar relationship with any News International product.

• Paul MacInnes asks who should be cast in Phone-Hacking: The Movie. He eye-catchingly suggests Hilary Swank ought to play James Murdoch.

The ACCC's preliminary finding is that the takeover could have competition issues, sending News Corp shares down 1.8%. The regulator insisted its decision had nothing to do with phone hacking.

10.22am:Paul Owen writes: Labour MP Tom Watson has said that he plans to refer to the police a claim that James Murdoch gave inaccurate evidence to the Commons culture committee this week. More as we get it.

10.42am:Peter Walker writes: Following on from that: Sky News is reporting that another Labour MP who has been central to pursuing News International over this story, Chris Bryant, has written to News Corporation's non-executive directors requesting that they suspend Rupert and James Murdoch from their roles.

10.48am:Peter Walker writes: On Comment is free, former No 10 media adviser Lance Price recalls his own full security vetting – "developed vetting" – before he took the job and expresses incredulity that Andy Coulson never underwent the same process. He suggests it would have been difficult for Coulson to have done his job without "developed vetting" clearance, but says:

No 10 must have found a way around all this because, by all accounts, Coulson was very effective at what he did. It is simply not credible that a Downing Street communications director didn't have access to everything he needed to see. The more pertinent question, therefore, is why he wasn't vetted at the highest level. If Coulson gave David Cameron all the assurances he needed before the appointment, presumably he could have told the security services what they wanted to hear as well. Except that it's the job of skilled investigators to probe into areas where even prime ministers may not wish to go.

11.09am:Paul Owen writes: David Cameron has said that James Murdoch "clearly has questions to answer in parliament", according to the BBC, following accusations that he misled the Commons culture committee on Tuesday.

Photograph: Andy Rain/EPA

11.18am: Paul Owen writes: Here are the full quotes from David Cameron (left) on James Murdoch and today's allegations about his evidence, courtesy of the Press Association news agency.

The prime minister said:

Clearly James Murdoch has got questions to answer in parliament and I am sure that he will do that. And clearly News International has got some big issues to deal with and a mess to clear up. That has to be done by the management of that company. In the end the management of a company must be an issue for the shareholders of that company.

PA also has details of the letter from Chris Bryant MP, who is taking legal action over claims that his phone was hacked, calling for the suspension of Rupert and James Murdoch from their roles in News Corporation. Bryant wrote to the non-executive directors of the firm that Rupert Murdoch's refusal to accept responsibility for what happened at the News of the World and his claim that it represented only a small part of his empire "in no way excuses the complete failure to tackle the original criminality at the company and the lackadaisical approach to such matters would suggest that there is no proper corporate governance within the company".

11.29am:Paul Owen writes: The Guardian established last night that Craig Oliver, Andy Coulson's successor as No 10 communications chief, is currently undergoing the higher level "developed vetting" process to which Coulson was not subject.

Coulson's predecessors Alastair Campbell, Dave Hill and Michael Ellam were all checked to "developed vetting" level too. David Cameron's deputy press secretary, Gabby Bertin, who was Coulson's No 2, is currently undergoing the full checks.

Coulson was only checked to the level below "developed vetting", called "security check".

In former assistant commissioner John Yates's testimony to the Commons home affairs committee on Tuesday, Yates described having spoken to Coulson "at No 10, with other officials … about counter-terrorism, police reform, and all the matters that I ought to be interested in".

John Yates: I have spoken to Mr Coulson at No. 10, with other officials.

Chair: When was that?

Yates: I will have to look in my diary. It was probably relatively early on. I think two or three officials were present.

Chair: About these matters?

Yates: No, no, about counter-terrorism, police reform, and all the matters that I ought to be interested in.

"Security check" level does allow access to such material in certain circumstances, but this would depend on exactly what was discussed and who else was present. It allows "occasional controlled access" to "top secret material". Someone with only security check would not be able to choose what top secret material they saw, or get unsupervised access to it.

We are preparing a list of further questions to put to Downing Street about the vetting of Coulson. In the meantime, we would like to hear from current and former civil servants and special advisers who may be able to help us discover:

• Who approved Coulson's mid-level vetting?

• Was Coulson asked to take "developed vetting" and refused?

• Was David Cameron aware of this?

• Did civil servants or special advisers who came into contact with Coulson know he was only vetted to "security check" level?

11.39am:Paul Owen writes: Here is the key part of James Murdoch's testimony to the culture committee on Tuesday, when he said he was not aware of the so-called "for Neville" email that would have blown a hole in News International's defence that hacking was limited to one "rogue reporter".

Tom Watson: James—sorry, if I may call you James, to differentiate—when you signed off the Taylor payment, did you see or were you made aware of the full Neville e-mail, the transcript of the hacked voicemail messages?

James Murdoch: No, I was not aware of that at the time.

Colin Myler, editor of the News of the World until it shut two weeks ago, and Tom Crone, the paper's former head of legal affairs, said in their statement last night that "we did inform him of the 'for Neville' email" – accusing Murdoch of misleading the select committee.

John Whittingdale, the chairman of the culture committee, said yesterday that the "for Neville" email "was seen as one of the few available pieces of evidence showing that this activity was not confined just to Clive Goodman", the only journalist prosecuted (and jailed) so far for phone hacking at the News of the World. The email contained a voicemail transcript marked "for Neville", assumed to be Neville Thurlbeck, the News of the World's chief reporter.

The email is believed to have been critical in News International's decision to pay Gordon Taylor, chief executive of the Professional Footballers' Association, so large a sum as £700,000 in out-of-court settlement after he threatened to sue the paper.

11.53am:Peter Walker writes: Fancy becoming the new commissioner of the Metropolitan police? The formal notice for applications to replace Sir Paul Stephenson has now been issued. The main point of interest is that the new appointee will be named in September "at the latest". The contact – barring unexpected scandal – lasts five years.

Miskiw declined to say if he expected to be arrested or whether he authorised hacking at the newspaper, or if he had hacked the voicemail of Milly Dowler, the Surrey schoolgirl who was murdered in 2002.

12.10pm: The US justice department is preparing subpoenas as part of preliminary investigations into News Corporation relating to alleged foreign bribery and alleged hacking of 9/11 victims' answerphone messages, the Wall Street Journal is reporting. More as we get it.

12.23pm:Peter Walker writes: John Whittingdale, the Tory MP who chairs the culture select committee, which heard from James Murdoch on Tuesday, has just been speaking on Sky TV. He confirmed the committee would be seeking clarification from Murdoch about his evidence following the intervention of his former colleagues. More details in a minute.

12.25pm:Paul Owen writes: The Wall Street Journal is reporting that the US department of justice is "preparing subpoenas as part of preliminary investigations" into Rupert Murdoch's News Corporation. The subpoenas relate to alleged foreign bribery – presumably News International's alleged payments to police in Britain, the subject of the Metropolitan police's Operation Elveden – and alleged hacking of the answerphone messages of 9/11 victims, a story reported by the Daily Mirror which has not been confirmed elsewhere.

Rupert Murdoch made it clear in his testimony to the culture committee on Tuesday that he considers the Wall Street Journal the jewel in his crown. On Monday the Journal published a leading article attacking the Guardian and the BBC for their coverage of the phone-hacking story and stoutly defending their owners, News Corp.

Today's piece says the justice department subpoenas require approval by senior figures in the department, which has not happened yet.

The US justice department has said it is looking into the police bribes allegations, and separately the FBI has said it has begun an inquiry into the 9/11 voicemail allegations.

The Journal also says News Corp is bracing itself for a possible investigation by the Securities and Exchange Commission into whether bribes to police broke the US Foreign Corrupt Practises Act (FCPA).

The paper notes:

For the Justice Department and the SEC to pursue News Corp. in the U.S. for allegedly bribing British policemen, the agencies would have to rely on a broad interpretation of the FCPA, legal experts say.

The WSJ story features this quote from a News Corporation spokeswoman:

We have not seen any evidence to suggest there was any hacking of 9/11 victim's phones, nor has anybody corroborated what are clearly very serious allegations. The story arose when an unidentified person speculated to the Daily Mirror about whether it happened. That paper printed the anonymous speculation, which has since mushroomed in the broader media with no substantiation … [The company has not seen any] indication of a connection or similarity between the events, allegations and practices being investigated in the UK and News Corp's US properties.

12.27pm: James Murdoch could be imprisoned or fined if the House of Commons finds he told lies to the culture select committee this week, writes Owen Bowcott, the Guardian's legal affairs correspondent.

Imprisonment or a substantial fine could theoretically be imposed as a punishment by parliament on anyone who told lies in evidence to a select committee.

Misleading MPs is deemed to amount to a "contempt of the house" in the same way that refusing to answer a summons to appear before a committee is reported to the Commons. The offender could then be summoned to the bar of the House.

The problem is that the sanctions - involving fine or imprisonment - to enforce any punishment are constitutionally somewhat rusty. Vernon Bogdanor, the former professor of government at Oxford University, has suggested they may have fallen into "desuetude" (disuse).

The House of Commons is not believed to have fined anybody since 1666 and has not "committed anyone to custody", apart from temporarily detaining them, since the 19th century.

12.33pm:Peter Walker writes: Here's what John Whittingdale had to say about the "for Neville" email (see 11.39am) at the centre of the disagreement:

I think it's a very important piece of information and I suspect that if James Murdoch had had it drawn to his attention that he would remember it.

Quizzed on whether the select committee should have pressed James Murdoch further on this, he continued:

We did ask him about it and he told us he'd never seen it. That's why this has arisen today. We said in our original report two years ago that we thought this was the single most significant piece of evidence which suggested that other were more widely involved [in phone hacking], but the evidence of James and Rupert Murdoch to us was that they had no knowledge ... That's the matter we will now want to press him on and to get his clarification.

Asked if he now thought James Murdoch had been "full and frank" with the committee, Whittingdale said:

All I can say is that what he told us is not the same as what Colin Myler and Tom Crone are saying to us. So we will need to find out how he responds to their statement, and that's something we will be inviting him to do.

Photograph: Martin Argles for the Guardian

12.48pm:Paul Owen writes: Tom Watson (left), the culture committee member who has been a key critic of News international, has been outspoken this morning about Colin Myler and Tom Crone's contradiction of James Murdoch's evidence (see 11.39am).

Watson told the BBC that if Myler and Crone were correct it meant Murdoch had "bought the silence" of Gordon Taylor when it agreed to pay him around £700,000 to settle his litigation.

Watson said of Murdoch:

It shows that he not only failed to report a crime to the police, but because there was a confidentiality clause involved in the settlement, it means that he bought the silence of Gordon Taylor and that could mean that he is facing investigation for perverting the course of justice.

He said Taylor was paid a settlement that was 10 times higher than the previous highest settlement, which was the News of the World's £60,000 payment to Max Moseley over a story about the then-Formula One chief's sex life. Watson went on:

Taylor was the victim of a crime. Far from reporting the crime to the police or putting the matter right within his own company, what Myler's statement shows - if it is true - [is] that James Murdoch knowingly bought the silence of Taylor, thereby covering up a crime. In the UK, that is called conspiring to pervert the course of justice and it is very serious matter, and I think the Metropolitan police now have to look at this as a matter of urgency.

He said he thought the police would want to investigate Myler and Crone, and added:

It is remarkable that this week, with the global media pantomime of Rupert and James Murdoch coming to parliament, broadcast live on every news channel around the world and then 48 hours later a senior editor and a lawyer are saying parliament was once again misled. I have never known anything like it in all my time in politics.

Photograph: Matthew Fearn/PA

12.55pm: Lord Goldsmith (left), the former attorney general, has denied claims that he overlooked widespread allegations of phone hacking in 2006 in favour of a "much narrower" investigation, reports Hélène Mulholland.

In a sideswipe at the former director of public prosecutions, Lord (Ken) Macdonald, Goldsmith said questions over the decision not to widen the investigation should be laid at the door of both Macdonald and the police.

Goldsmith, who served as attorney general under Labour from 2001 until 2007, told BBC2's Newsnight last night that the suggestion that he had approved, "indeed instructed, to conduct only a narrow only an investigation" was "absolutely not true".

Goldsmith said:

The DPP is the person who is the conduit, if you will, to the attorney general, not the police. It is the police who were investigating. It appears they were seeking advice from the Crown Prosecution Service under the DPP and I'm sure the explanation that they give as to what took place is really what one should be looking at.

Goldsmith issued his strong rebuttal following claims made by Conservative MP Geoffrey Cox in the Commons on Wednesday that the Labour peer had been informed that a "vast array of numbers had been tapped" by private investigators at News International.

Cox went on to say that Goldsmith gave his approval for the police inquiry to focus on News of the World royal reporter Clive Goodman and private detective Glenn Mulcaire, who were later convicted.

Pressed on Newsnight to say whether he had asked for more details about the other allegations at the time, Goldsmith said it wasn't his job to do that. "Why not ask Ken Macdonald more about what took place ... I look forward to hear what he has to say about that."

Goldsmith said he was briefed at the time about the case relating to Mulcaire and Goodman, and had been told that there were other cases and there were talks about further investigations "in due course".

I wasn't told about any of the other allegations as I've said. As background in the briefing that I had about those cases [Mulcaire and Goodman's], I was told that the police believed there were other cases as well, but they were talked about in terms of there being probably further investigations in due course.

And I think the point to make absolutely plain was that there was never any request to me, still less was there any answer from me, suggesting that the inquiry should be kept narrow.

Goldsmith also stressed that "no government ministers knew anything about this", because he said it would be "quite wrong as attorney general to tell other ministers about ongoing police investigations".

12.58pm: The Law Society has been contacted by solicitors who say the police have notified them that their phones may have been hacked by News of the World journalists.

1.06pm:Paul Owen writes: The Guardian has put eight questions to the government regarding Andy Coulson's security clearance as No 10 communications chief. Coulson did not undergo the high-level "developed vetting" that his predecessors and successor have been subject to, instead undergoing only the lower level "security check" (see 11.29am).

1. Was Andy Coulson asked to undergo developed vetting (DV)?

2. Did Coulson decline to undergo developed vetting?

3. Which Downing Street and/or Cabinet Office officials decided that it would be appropriate for Coulson to be vetted at the lower "security check" level?

4. Was the prime minister involved in the decision to have Coulson vetted at the lower SC level, or informed after it was taken by officials?

5. Were other officials and ministers who might ordinarily have expected a No 10 press secretary to have DV clearance informed that he was not vetted to that level?

6. What meetings did Coulson attend relating to national security issues, the war in Afghanistan or counter-terrorism?

7. Was Coulson interviewed as part of the process of his security vetting?

8. If it was not considered necessary for Coulson to have DV clearance why are both his successor and his former deputy undergoing developed vetting?

We will post the answers as soon as we get them.

1.22pm: John Whittingdale, the chairman of the culture committee, has confirmed that his committee is to send James Murdoch a letter next week with a series of questions that he could not answer at the hearing – as well as asking him to respond to Myler and Crone's allegations (see 11.39am).

The precise nature of News International's waiver here means Harbottles will still not be able to go around declaring its innocence; it will have to wait until asked questions by the police or parliament.

However, there is one exception to the privilege rule: if the lawyer is used, knowingly or unknowingly, to commit or cover up a crime or serious fraud, then he can disclose what he knows.

So if it turned out, hypothetically, that News International deliberately withheld information so that Harbottles came to the conclusion it did, allowing News International to trumpet that finding in a bid to mislead investigators about the extent of wrongdoing at the company, then the privilege could be broken. There is no suggestion, of course, that the company did do this.

"If I was in that situation, I'd rather err on the side of professional caution and not risk having the Solicitors Regulation Authority come down on me," he says.

2.45pm: John Whittingdale has just spoken live to BBC news, saying much what he did on Sky earlier (see 12.33pm).

In a curious twist, he was speaking just outside the National Shooting Centre in Bisley, Surrey, where he had just captained a team of MPs to victory in their annual rifle competition against the House of Lords. "Don't worry, I'm not in a war zone," he reassured viewers as the sound of shots rang out behind him.

3.09pm:Paul Owen writes: Former assistant commissioner John Yates is suing the London Evening Standard for libel "over aspects of its reporting of his conduct in the News of the World phone-hacking investigation", his solicitors, Carter-Ruck, have just announced.

The solicitors say the claim relates to allegations made in articles published on 7 July 2011.

Luke Staiano of Carter-Ruck, Yates's solicitor, said:

The Evening Standard published highly defamatory allegations concerning Assistant Commissioner Yates which go to the heart of his integrity as a police officer. The allegations are completely false and without foundation. The newspaper made no effort to contact Mr Yates to verify the accuracy of the allegations and even wrongly claimed in the article that Mr Yates had not responded to calls. The Evening Standard has refused to apologise or withdraw the allegations, leaving Mr Yates with no alternative but to bring legal proceedings.

3.27pm:Ian Katz writes: Andy Coulson (left) had begun undergoing high security vetting in November, around three months before he resigned as David Cameron's director of communications, the Guardian has learned.

Downing Street has been under pressure to explain why the former News of the World editor was not subjected to so-called "developed vetting", the high security checking process most previous No 10 press secretaries have undergone. Both Coulson's successor and his former deputy, Gabby Bertin, are undergoing developed vetting.

A Whitehall source said the decision not to subject Coulson to developed vetting was taken by Jeremy Heywood, the Downing Street permanent secretary. The source said it was decided that, as director of communications, Coulson did not need access to highly secret material and that developed vetting was a costly, unnecessary expense.

The source stressed that Coulson's lower level of clearance, "security check" or SC, did allow him to have access to material designated "secret" and to "top secret" material under supervision. He also said that the controversy surrounding Tony Blair's press chief Alastair Campbell's access to intelligence material was a consideration in deciding to give Coulson a lower level of vetting.

The source said that following the discovery of an explosive device on a plane at East Midlands airport in October, it was decided that Coulson did need developed vetting to deal with similar terrorism-related issues and the process was started. The process can take three to six months and had not been completed when Coulson resigned saying the phone-hacking scandal meant he could no longer work effectively.

The New York Times published a major investigation of the phone-hacking scandal in September 2010 that prompted the Metropolitan police to open a limited inquiry and end its relationship with Neil Wallis, Coulson's former deputy, who was working as a £1,000 a day PR advisor to the Met. The source insisted the decision to subject Coulson to developed vetting was not connected to the New York Times report or the spate of coverage in the UK media that followed it.

It is still not known whether David Cameron was informed of the decision not to vet Coulson to the higher level on entering Downing Street in May 2010, or the decision to begin the process in November 2010. The source said he did not believe Coulson had received any indication of the likely outcome of his DV process when he resigned in January.

The Guardian has asked Downing Street and the Cabinet Office whether Coulson was consulted on what level of security vetting he would undergo on entering Downing Street.

We do not comment on the vetting level or status of individual current/former members of staff. However, the PM commented on Andy Coulson in the house on Wednesday 19 July. The PM said: "He was vetted. He wasn't able to see most sensitive documents in government. He obeyed that code of conduct."

That said anyone working in the prime minister's office is of course subject to National Security Vetting at a higher level than most departments.

The type of vetting undertaken will depend on the level of access they require to sensitive information and other factors, and Andy Coulson, like all civil servants and special advisers, was vetted to the level appropriate to the information he has access to.

• James Murdoch is under pressure over part of the testimony he gave to the culture committee on Tuesday. He said he was not aware of a key email that would have undermined News International's contention that hacking was limited to "rogue reporter"; yesterday two key former News of the World figures said that they had told him about this email (see 11.39am). Tom Watson, a key critic of News International and member of the committee, said he would refer the matter to the police. He said that if Colin Myler and Tom Crone were correct it meant Murdoch had "bought the silence" of Gordon Taylor when it agreed to pay him around £700,000 to settle his litigation (see 12.48pm). John Whittingdale, the chairman of the culture committee, has written to Murdoch asking him to respond to Myler and Crone's allegations (see 1.22pm). DavidCameron said Murdoch "clearly has questions to answer in parliament" (see 11.18am). Murdoch could be imprisoned or fined if he is found to have told lies to the committee, although the sanctions have not been used for at least a century (see 12.27pm). Here's Hélène Mulholland's latest story on the accusations against Murdoch.

• Andy Coulson had begun undergoing high security vetting in November 2010, around three months before he resigned as No 10's director of communications, the Guardian has learned (see 3.27pm). A Whitehall source said that the decision not to subject Coulson to "developed vetting" initially – a level of checks his predecessors and successor have undergone – was taken by Jeremy Heywood, the Downing Street permanent secretary, on the grounds that he did not need access to highly secret material. The controversy surrounding Tony Blair's press chief Alastair Campbell's access to intelligence material was a consideration in deciding to give Coulson a lower level of vetting. The decision to reverse course and subject him to developed vetting was taken after the discovery of a bomb on a plane at East Midlands airport in October 2010. It is still not known whether David Cameron was informed of the decision not to vet Coulson to the higher level on entering Downing Street in May 2010, or the decision to begin the process in November 2011.

• The US department of justice is preparing subpoenas as part of preliminary investigations into News Corporation, according to a report in News Corp's Wall Street Journal (see 12.25pm). The subpoenas relate to alleged foreign bribery – presumably News International's alleged payments to police in Britain, the subject of the Metropolitan police's Operation Elveden – and alleged hacking of the answerphone messages of 9/11 victims, a story reported by the Daily Mirror which has not been confirmed elsewhere.

• Former assistant commissioner John Yates is suing the London Evening Standard for libel over its reporting of his conduct in the News of the World phone-hacking investigation (see 3.09pm).

• Labour MP Chris Bryant has written to News Corp's non-executive directors calling for the suspension of Rupert and James Murdoch because of their "complete failure to tackle the original criminality at the company" (see 11.18am).

• Lord Goldsmith, the former attorney general, has denied claims that he overlooked widespread allegations of phone hacking in 2006 in favour of a "much narrower" investigation (see 12.55pm).

4.13pm: A point we missed earlier: Scotland Yard has confirmed that it has received Tom Watson's letter regarding James Murdoch's testimony to the culture committee. The letter is "being considered".

4.38pm: In the US, pressure group MoveOn.org has released a 30-second advert calling on viewers to "call Congress and demand a full investigation into Rupert Murdoch's News Corp". MoveOn says a recent poll by SurveyUSA showed that 73% of the American public wants an investigation into the alleged culture of corruption at News Corporation.

4.50pm:Ed Pilkington writes from New York about the US justice department's reported preparations to subpoena News Corporation in its investigation into whether the company broke anti-bribery and hacking laws on both sides of the Atlantic. Ed writes:

The disclosure that subpoenas are actively being drawn up within the US, reported by News Corp's flagship newspaper the Wall Street Journal, comes a week after the attorney general Eric Holder announced that he was launching a preliminary investigation into the media group as a result of the UK phone-hacking scandal. According to the Journal, the subpoenas will be broadly cast to draw information from the company relevant to the investigation, though final approval has yet to be granted by top justice department officials.

In addition, it has emerged that federal prosecutors have begun probing allegations that News Corp's advertising arm in America hacked into a computer of a competitor as part of a campaign to crush its rival. A lawyer for the smaller company, Floorgraphics, has told NBC that he was visited this week by two federal prosecutors and an FBI agent.

News Corporation declined to comment on the legal moves.

Mary Mulligan, a former federal prosecutor in the southern district of New York that handles many of the big corporate cases of this sort, said that there are numerous directions in which the probe of News Corp could be taken. "This is a complicated investigation, and a very important matter that's being looked into."

She added that the FBI and other federal agents would be guided by what they found in terms of any evidence of phone hacking in the US or News Corp responsibility abroad. "The facts are going to drive any charges that arise – what was accessed, how it was accessed and where."

One specific allegation that the FBI is investigating is whether News of the World journalists attempted to gain access to the phone records of 9/11 victims. The claim was raised in a report by the Daily Mirror though so far no solid evidence has emerged to support it.

Were the accusations confirmed, News Corporation could be susceptible to prosecution under Title 18 USC 2701, involving unlawful access to stored communications, or 2703 and 2704 were the cell phone messages found to have been stored on a separate server.

News Corporation also faces a possibly lengthy and expensive federal probe into whether it broke anti-bribery laws as part of the illegal News of the World phone hacking in the UK. The company is potentially liable under the Foreign Corrupt Practices Act that bans US-based companies from profiting from bribery and corruption in other countries.

News Corp is a US-based firm headquartered in Manhattan. FCPA experts have suggested that it could be brought under the auspices of the act because News of the World journalists bribed police officers in the UK in search for exclusive stories that in turn increased sales and generated profits.

It is not a defence for News Corp executives to argue that they were unaware of the bribery. Under the FCPA, a company can still be penalised if it should have know – what is called in legalise "willful blindness".

News Corp could also come under the scrutiny of the US Securities and Exchange Commission that is jointly responsible with the justice department for policing the FCPA. The SEC will want to know whether News Corp properly declared all its activities in its accounts or whether it tried to hide any bribes made within the UK under false accounting returns.

It is not known precisely what information investigators are seeking from News Corp under the subpoenas, but it could include News of the World financial books which would then be examined by forensic accountants.

News Corp itself seems to be most anxious about the FCPA side of the federal investigations, judging from the legal team it has assembled. Over the past week it has employed some of the heaviest hitters in American legal affairs.

They include Brendan Sullivan, a formidable trial lawyer once described as "the legal equivalent of nuclear war", and Mark Mendelsohn who used to head the justice department section that decides which FCPA cases to prosecute.

He is joined by Michael Mukasey, a former US attorney general, and his legal partner Mary Jo White who represented Siemens in one of the largest FCPA cases in history.

In a press release, the SRA says: "We will pursue our investigation vigorously and thoroughly, but emphasise that our inquiries are at an early stage, and no conclusions have been reached about whether there may have been any impropriety by any solicitor."

The Crown has already asked Strathclyde Police to make a "preliminary assessment" of the available information and the evidence given by certain witnesses in Sheridan's trial in light of allegations made against the News of the World newspaper.They did not say which witnesses are being investigated but former News of the World editor Andy Coulson, Scottish News of the World editor Bob Bird and reporter Douglas Wight all gave evidence.A Crown Office spokesman said: "Strathclyde Police have now reviewed the available information and following liaison with the area procurator fiscal at Glasgow, the Crown has instructed an investigation should commence. The investigation will be progressed expeditiously and in close liaison with the area procurator fiscal and Crown counsel."Significant resources will be deployed, though these will vary with the needs of the investigation."Police will investigate allegations that witnesses gave false evidence in the perjury trial and whether data protection laws have been broken and whether personal data was illegally accessed in Scotland.It will also look at any offences uncovered in material held by Metropolitan Police connected to phone hacking, as well as allegations of police corruption.

6.19pm: Strathclyde Police will also investigate claims of phone hacking and breaches of data protection in Scotland, PA reports.

6.25pm: Here's Josh Halliday's report on suspicions that Will Lewis, a senior executive at News Corporation, was involved in orchestrating the disclosure of Vince Cable's comments about Rupert Murdoch, which were leaked to the BBC.

Josh writes:

An investigation by Kroll, published in part by Reuters on Friday, concluded that there was a strong suspicion that Lewis and another former Telegraph colleague – who also joined News Corp's UK publisher subsidiary News International last year – were "involved in orchestrating the leak of information" in order to damage their former employer.